I think Josephine has mentioned that it can be corrected surgically if it is a problem for the pig.
We first noted Lasix could help pea eye when the pea eye in a sow with a heart condition completely disappeared after a few weeks on Lasix.
Lasix is a harsh drug with cautions of its own(extremely dehydrating) so it shopuld not be used casually. Pigs with kidney conditions are NOT candidates for this treatment.
We only resort to the Lasix when the pea eye is causing the pig pain. So far it´s proven to be an effective control.